The present invention relates to an image forming apparatus by which an image is formed according to image data, and specifically to the improvement of a sorting operation at the time when a sheet on which an image is formed is ejected.
Generally, in an electrophotographic image forming apparatus such as a copier, printer, or the like, a document image is converted into electric signals (image data) corresponding to density in the document image information, and an electrostatic latent image is formed on a photoreceptor drum corresponding to the image data using laser light, or similar devices. The electrostatic latent image is developed and transferred onto a sheet as a toner image, and the toner image on the sheet is heated by a heater of a fixing device, and fused and fixed.
The sheets on which images are formed as described above, are needed to be sorted corresponding to the number of sets of sheets on which images are formed, and sorting is conducted by the following methods:
(1) The sheets are sorted such that the position is shifted for each set of sheets and the sheets are ejected (offset operation) by an ejecting and sorting device with a sorting function (finisher, sorter, etc.). PA1 (2) The sheets are sorted by staple processing by an ejecting and sorting device with a sorting function (finisher, sorter, etc.). PA1 (3) Image processing is conducted such that the image is rotated by 90.degree. by an image processing means by a key operation of the operator, and the image is formed on the sheet placed in the direction which coincides with the image processing condition and the sheet is outputted.
As described above, it is necessary that sorting is conducted by either of an ejecting and sorting device with a sorting function, or an operator's manual operation.
Further, sorting by the above-described ejecting and sorting device can be conducted only when the performance of the ejecting and sorting device (the sorting function is provided or not) or its mounting condition (the ejecting and sorting device with the sorting function is connected to the apparatus or not) is confirmed and the sorting operation can be conducted.
Accordingly, the sorting operation is difficult when the ejecting and sorting device is connected to a network and therefore it is difficult to confirm whether the sorting function is provided or not. Further, the sorting operation can not be conducted in the following cases: the ejecting and sorting device with no sorting function is connected; the ejecting and sorting device with a sorting function is connected, but can not be used; and it is indicated to sort the sheets into bins more than the number of bins to be usable.